PROJECT ON RAIN WATER HARVESTING

FOR MANGALDAI TOWN

An initiative on newly elected MLA GURUJYOTI DAS

By Mir Kamaruz Zaman(Er. civil)

WHAT IS RAIN WATER HARVESTING

The harvesting of rain water simply involves the collection of water from surfaces on which rain falls, and subsequently storing this water for later use. Normally water is collected from the roofs of buildings and stored in rainwater tanks.

It is the accumulation and deposition of rainwater for reuse on site.

The harvested water can also be used as drinking water, long term storage and for other purposes such as ground water recharge.

ADVANTAGES

The technology is simple and easy to install.Local people can be easily trained to implement such

technology and construction material is easily available. It has low maintenance cost and running cost.Water collected from roof catchments usually is of acceptable

quality for domestic purpose.Rain water can be a continuous source of water supply for both

the rural and the poor.Depending upon the conditions both water collection capacity

and storage capacity can be increased as needed within the available catchment area.

DISADVANTAGES

Disadvantages are mainly due to the limited supply and uncertainty of rainfall.

SUITABILITY

The augmentation of municipal water supplies with harvested rainwater is suited to both urban and rural areas. The construction of cement jars or provision of gutters does not require very high skilled manpower.

SYSTEM OF RAIN WATER HARVESTING

Commonly used system s are constructed of three principal components. They are:-

Catchment areas:- This include roof catchment where rainwater is collected in simple vessels at the edge of the roof and land surface catchment which involves improving runoff capacity of land surface through various techniques including collection of runoff with drain pipes and storage of collected water.

Collection Devices:- Storage tanks for collecting rainwater harvested using guttering may be either above or below the ground. Precautions required in the use of storage tanks include provision of an adequate enclosure to minimize contamination from human, animal or other environmental contaminants.

Conveyance system:- It is required to transfer the rainwater collected on the roof tops to the storage tanks. This is usually accomplished by making connections to one or more down pipes connected to the rooftop gutter. Consideration should be given to the fact that when it first rains dirt and debries from the rooftop and gutters will be washed into the down pipe. Thus, the relatively clean water will only be available some time later in the storm.

METHODS OF RAIN WATER HARVESTING

Surface runoff harvesting:- In urban area rainwater flows away as surface runoff. This runoff could be caught and used for recharging aquifers by adopting appropriate methods.

Roof top rain water harvesting:- in this system the rain water is collected from the roofs and it can either be stored in a tank or can be diverted to artificial recharge system. This is less expensive and very effective and if implemented properly helps in augmenting the ground water level of the area. This system mainly constitutes of following sub components:-

i) Catchment ii) Transportation iii) First flush iv) Filter

Diagrams of rain water harvesting

Diagrams of rain water harvesting

Diagrams of rain water harvesting

Diagrams of rain water harvesting

Diagrams of rain water harvesting

Diagrams of rain water harvesting

IMPORTANCE OF RAIN WATER HARVESTING

1) The gathered rain water can be used for agricultural purposes. The environment may be helped to get rid of the tendency to drought.

2) The requirement of water for feeding the live stock can be met.

3) The ever increasing demand for water can be satisfied.4) The quantity of the subterranean water can be increased.5) Wastage of water flowing through drain, gutter, or any water

– course of any type may be stopped.6) Water-logging on roads and thoroughfares can be checked

and localities can be saved from being inundated.7) The quantity of water can be raised and soil erosion can be

checked.

SUGGESTIONSFor a small town such as Mangaldai we should try to harvest rain water from roof tops as it is less costly. We should try it first in:-i. Government buildingsii. Officesiii. Courtsiv. Government bungalowsv. Public buildingsvi. Public toilets

We than check the effectiveness and efficiency of this system and proceed further for every household in town and try harvesting the surface runoff also. This will further reduce the water logging problem of our town and also would solve the problem of water supply in the town and nearby areas.